Aircraft having sustaining rotors



Aug- 21, 1934 y J. s. PECKER 1,971,016

AIRCRAFT HAVING SUS'IIIIING'v ROTORS *l Filed Sept. 5, 1951 y 2 Sheets-Sheet 1 y NQNTR BY www ATTORNEYS Aug. 21, 1934. .1. s. PECKER AIRCRAFT HAVING SUSTAINING ROTORS 2 Sheets-Sheet 2 Filed sept. 5, 19:51

INVENTOR /mlfl/fw/ 'd I awww ATTORNEYS Patented Aug.'21, 1934 Uiu'riali'l STATESI AIRCRAFT rmvmd Joseph S. Pecker, Philadelphia, Pa., assigner to Autoglro Company of America, Philadelphia,

Pa., a corporation of Delaware application september s, im, sei-m No. 561,344

23 Claims. l

This invention relates to aircraft having sustaining rotors and is particularly concerned withga craft of the type in. which the rotor is composed of a plurality of sustaining blades li which are pivoted or articulated to an upright `axis structure.

Among the more important objects of the invention are simplification of the rotor blade mounting parts, the arrangement `of the mountl ing structure in general so that a minimum of parasite drag and the .like is=produced, and the provision of a mounting structure which, in general, is relatively small in Ioverall dimensions and weight.

As a further object, theinvention has in view a novel arrangement of means for controlling pivotal blade movements, the arrangement being such that a minimum of space -is occupied thereby and the parts being constructed so as to lie 2Q closely adjacent the central hub or axis mechanism, this being of importance as it still further reduces the overall dimensions of the rotor head as a whole and thus decreases parasite drag, skin friction, etc.

The general nature of the invention as well as objects and advantages in addition to those noted above will bemore apparent from a consideration of the following description making ference toY` the accompanying drawings, in.'

which;

Figure 1 is a somewhat diagrammatic side yelevational view of a craft of the type here involved, this craft being equipped withl aY rotor mount constructed in accordance with this invention; l f

Figure 2 is a vertical sectional viewy through the rotor mounting andaxis structure, this viewA `including a fragmentary showing of the root end of one oi'4 the sustaining blades as well as various other elements considered more in detail hereinafter; i

Figure 3 is a top view, partlfin plan and partly in horizontal section. of the hub structure illustrated in Figure 2; Figure 4 isa view in horizontal section, similar to Figure 3, of `a slightly 'modified structure; and A A A Figure 5illustrates' another modification. I'he type of craft with which the present invention is concerned, such being. illustrated in Figure 1, is ,provided with forward propelling means including an engine 5 anda propeller 6 mounted at the forwardend of the fuselagefl. At therear end ofthe fuselage an empennage structure 8 is provided and suitable landing gear 9 may be disposed below the body preferably v in the vicinity of the supplementary fixed wings The rotor system is composed of `a. plurality of, blades 11 which are mounted on the axis 60 mechanism'indicated generally at l2, the latter being supported, preferably above a cockpit 13 `of the fuselage, as by means of post or leg ele,4 ments 14 and 15.' In order that the blades may be free independently to assume various posi-V 05 tions of equilibrium under ,the inuence of inertia, lift and other forces of flight, they are preferably pivoted on tw different axes to the central hub mechanism. One of these axes `is e indicated by the reference numerall 16, this one being extended substantially horizontally, while the vother one -appears at l'l andas shown, is extended generally vertically. The showing of ,the articulations in'Figure l, of course, is diagrammatic, and it is noted that these structures u are considered more in detail hereinafter,

. f Rotor driving means, especially adapted to initiate rotation of the blade system prior to takeoif, may also beprovided and, in Figure 11,' a `driving shaft 1a is illustrated es extended ob- 00 liqueiy upwardly from the fuselage of the craft Just rearwardly Aof the engine 5 to a point adia- 'centto the apexiistructure 19 on whichthe axis 12is mounted. vVarious features of a starter or 7liriving mechanism of the type more or less 35 diagrammatically illustrated' in Figure 1 constitutethe basis of my copending application.

Serial yN0..5l2,383',"liled January 30th, 1 931.

From inspection of Figures 2 and 3 it will be seen: that the apex structure 419, which is'sup- 9 ported at thejtop of the post or leg" elements 14-15, is provided with--asocket 20 adapted to receive the internal spindle or shaft 2 1. This spindle 21 is rigidly secured in itssocket 20 by means of a `flange 21u. which abnts against 9 the upper edge of thesocket 20, when the securing nut 2lb is tightened in position. The flange 21a.` may also Ibe recessed at `one or more points in order to receive one or more upward No projectionsv or lugs 20a which are formed at the upper edge of the socket 20 and which thus serve to positivelyprevent relative rotation of thinternal spindle 21 and the spindle socket. L, Ball bearings22, A23 and 24 are arranged 105 around the spindle 21, at least two of these -bearings being vertically spacedfrom each other byjneans ofv a spacer 23a in order effectively to ""take the radial loads .during rotation of the um, Thehead structurepof course, also inll0 engagement.

positioning bolt (31h) is employed in order to surface thereof. -pins 28 and 31 provides for positioning of the cludes a rotatable hub part 25 which is mounted to rotate on the bearings 22, 23 and 24.

' The main rotor bearings 22, 23 and 24 as well as the spacer 23a are also secured to the central spindle 21 by means of a nut device or structurel 21c which reacts, throughthe inner bearing races and the spacer 23a, against 'the spindle flange 21a. The flange 21a of the spindle 21, therefore, serves not only as an abutment against which the nut 2lb may react in securing the rotor, as a whole, to the supporting structure, butals'o as an abutment for use in positioning the various bearings which are disposed between the two primary and relatively rotatable axis parts. j

As in the copending application Cierva, Serial No. 145,655, filed November 1st, 1926, theblades 11 are each provided with two pivoted joints which serve to connect them to the hub 25. In accordance with this invention, however, the substantially vertically extended pivot axis for each blade is disposed between the axis of the hub vas a whole and a substantially horizontally extended blade pivot axis. As

appears most clearly in Figures 2 and 3, ajpair of lugs 26-27, for each blade, is extended outwardly from the hub member 25 at points adjacent to the bearings 23 and 24 and these lugs are vertically apertured to receive the pivot pin 28. Bearing bushings 29 may also be interposed between the pin 28 and the lugs 26 and 27.

A joint part 30 is mounted around the pin 28 between the lugs 26 and 27 and is apertured horizontally to receive the pivot pin 31. connection to the, blade is completedby means of apertured fork parts'32-32 which are arranged at the. end of the blade root 11a. The forks, of course, are also apertured lto receive the pin 31 so that two articulations or pivot joints are provided between the blade itself and the hub structure 25. Bearing bushings 33 may be interposed between the pin 31 and the forks In order-'to prevent rotation as well as longitudinal displacement of thepin 31, I preferably employ a bolt 31b which is threaded -\into the joint part' 30 and has its inner end extended into a complementary groove formed substantially tangentially of the pin 31. It will also be observed, as indicated at 31o, that the horizontal pin 31 is extended generally tangentially of the pin 28 and ts into a recess formed in the outer This interengagement of the apparent that longitudinal displacement aswell" as rotation of the pin 28 is prevented by such Thus, only a single removable position both the horizontal and vertical articulation pins for each blade.

By arranging the blade pivots in the mann above described, the vertical articulation may conveniently be brought in closely adjacent to the hub, as clearly shown in the drawings, so

"that, in effect, the blade articulations, .together with the central hub parts, constitute only one single mass or structure, with the result that, in flight, skin friction and parasite drag are reduced to a minimum.

It is also to be observed that the arrangement shown provides for a compact head structure in view of the fact that the horizontal articulation may also be brought-in relatively close to the vertical pivots. As a further advantage of of Juan de la The,

this construction, it is to be observed that the lugs 26-27 may conveniently be disposed radlally outwardly of the ball bearings 23 and 24 so thatl the strains, thrusts and the like of flight operation are eillciently distributed and transmitted to the central and fixed spindle 21. It is further to be observed that the upper and lower flanges 25a. and 25h of the 4hub member are disposed in the general planes in which the lugs 26 and 27 as well as the bearings 23 and 24 are located. The relative disposition of these flanges, the bearings and the blade attaching lugs is of considerable advantage in providing adequate strengthas against' all the stresses of flight operation, especially since the flanges serve as reenforcements in the regions where the loads are more or less concentrated. Theanges 25a and 25h also serve additional purposes referred to hereinafter.

ments or the blades. this part a4' being extended m 10o such manner as to lie between the blade forks 32-32, and contact with the base of the blade. root member 11a. The. stop 34 may convenlently be attached to the joint part 30 by means of the pin setting bolt 31b and/or an additional 105 bolt or bolts such as indicated at 34a.

'36, as appears most clearly in Figure 3, are

disposed between the abutments 35 and a portion of the hub 25, so that they utilize space vclosely adjacent to the hub which is well shield-l ed. Thus they do not add to the parasite drag or skin friction of the head as a whole. These blocks 36, according to this form, are secured to and carried by the abutments 35 by means 11204 of bracket members 36a, the latter being attached to the abutments themselves as by means of bolts 36D. i

For purposes of lubrication, I preferably construct' the two pivot pins 28 and 31 with central 125 apertures or bores 28a and 31a which may conveniently serve as a reservoir for oil or grease,- preferably the latter. The lubricant may be introduced through suitable fittings such as indicated at 37 and a port 38, disposed at the point 130 where the pins interengage, may be provided so that lubricant may pass between the bores of the ltwo pins. 'I'he lubricant may suitably be fed, under the influence of centrifugal force, through the ports 39these being provided between the interior of eachV one of the pins and the bearing bushings surrounding them. Certain features of lubrication of this general type are described and claimed in the copendlng ap- 'plication of Agnew E. Larsen and Joseph 8.140`

hub flange 25a as clearly seen in Figure 2. 150

self.

'I'he mounting of the blade supporting elements 41 preferably includes two pivot joints 41a and 41h which connect the element 41 proper to a bushing 41e the latter being mounted with free" includes a downwardly open drum 42 `securedl to the hub 25 and serving to house 'internal brake parts 43. Thedrum 42 is secured to the lower hub flange 25h and is also arranged to support the ring gear 44 which is adapted to cooperate with the pinion diagrammatically indicated at 45 in Figurez, this pinion being a portion of the rotor driving mechanism. 'Ihe brake mechanism forms no part of the present invention per se but is desciribed and claimed in my copending application, ASerial No. 545,451, filed June 19th, 1931.

According to the foregoing, the present invention provides a rotor head structure, all the parts of which are compactly arranged so that parasite drag and the like are reduced to a' minimum. At the same time, the various bearings and blade joints are so constructedas to.

withstand relatively heavy strains and stresses, with an ample margin ofrs'afety, even though the parts themselves are of relatively small size and total weight.

Turning. now to the modification of Figure 4 attention is called to the fact that the general arrangement of hub and blade joint parts is quite similar to that of Figures 2 land 3. According to this arrangement, however, the blade jointA part 30a is not provided with stops or abutments such as those indicated at 35 in vFigure 3. In place of this arrangement I have constructed the blade-forks 32a-32a .in such manner as to serve as the abutment against which the 4rubber blocks 46 react. As a further modification, the arrangement of Figure 4 includes only a single rubber block mounted adja'cent to the hub between each of the adjacent blade attaching lugs 26a. Each block 46, furthermore, is embraced by-a bracket or clip 47, having flanges at top and bottom which, in turn, is secured to the webs 48 vextended between the blade attaching lugs as by means of a bolt or pin 49.

In Figure a further modification of`blade movement controlling means is illustrated. This structure is also somewhat similar to the showing of Figure 3 but, in this instance, the individual resilient `blocks 50 are mounted within sockets 51 formed at one side of the abutments 35a.' Each block may be secured in place by means of a bolt 52 threaded into a collar 53 which latter may be moulded into the block it- By this means, the mounting for the resilient bumpers isl considerably simplified, it being noted particularly that no bracket mem'- bers need be` employed in order to position and secure them. As shown, furthermore, the bumpers 50, when the blade is in neutral position, are somewhat spaced from the hub member-25, although it should be understood that, if desired-- the arrangement may be modified so that the bumpers 50. similarly to those indicated at 36 ures 3 and 5, it will be seen that the abutments in Figure 3, will remain under compression at all times. At this point it should be observed that th general blade articulation arrangement of all forms of hub structure herein illustrated provides for the disposition of blade movement control means closely adjacent to the hub itself so that a neat and compact structureresults. The particular pivot arrangement, furthermore, is adaptable to a number of different types of blade movement controlling means as will readily be apparent from inspection of Figures 3, 4 and 5. In Figure 3 the bumpers 36 are illustrated as being under compression at all times, while in Figures 4 and 5, the arrangements are such that the rubber blocks come into operation only after a given or predetermined angular displacement of the blades about their vertical articulations. Furthermore, in Figures 3 and 5, a pair of, cushions is employed for each blade, while in Figure 4, each one-of the blocks ern ployed cooperates with two adjacent blades in order to control movements about `their vertical' articulations. Finally, Afrom comparison of Figor stops associated with the joint part 30, as well as the associated rubber blocks, mayA be arranged either to remain under compression at all times or to come into operation only after a given angular displacement of the blades.

Thus, where various characteristics of the craft as a whole indicate that one or the other of the control mechanisms should be employed, this may readily be done, since the general arrangement of the parts is universal in character, that is, any one of a number of different blade movement control devices may conveniently be applied between the hub structure andthe blade fork itself oran abutment moving therewith. V

Finally, it should be observed that the novel arrangement of blade pivots or articulations is such that the horizontal as well as the vertical joints may conveniently be brought in very close to the rotorhead. 'Ihis is of substantial im- 120 Y made relatively light in construction. This arm rangement is also desirable since the blade attaching lugs are disposed closely adjacent to themain rotor hub bearings, the result of this being substantially direct transmission of thrust to the central and fixed axis part. The strength of this general structure is further increased by the disposition of flanges or ribs adjacent the upper and lower edges of the hub part proper,

lthese ribs serving, in addition, as a means of attachment of the rotor tip or cone 40 and the 140 rotor brake drum 42.

It is further observed thatthe two pivotl pins for each blade are fixed in a single joint part of very small overall dimensions, it being noted that this block is. provided with a pair of bores extended prpendicularly to each other so that the lugs 26 and 27 of the hub 25 as well as the blade forks 32-32 embrace the joint block and, indeed, even overlap somewhat with respect to each other. In this way, the joint parts are 15 85 ,bearings to provide cent to each.

constructed to occupy a minimum of -space. The very`simplicity and small dimensions of the blade joints, particularly the block part 80, in addition to reducing drag and total weight,

.I also increases the strength of the structure as a whole.` f

The interengagement' oi'- the horizontal jansi- `vertical pivot pins for each blade is also of advantage as it permits 'the use of a very simple l0. means for positioning and securing the pins ir their operative positions. This construction is also advantageous in permitting the use of a lubricant ductextended between the reservoirs provided in the pins, so that, in eifect,v the pin 18. cavities are joined in onerelatively large reser'- voir and, when suitably packed with grease, thorough lubrication of both pins will always be provided. i

A further advantage of the structure above il described resides in the fact that the hub 'member proper is of such configuration that `its manufacture is .greatly simplified ascompared with` hub structures heretofore employed.A In this connection, it is noted that substantially no $5 :milling work need .be performed for the reason that the various lugs, flanges, etc., may readily be turned ina v ery. simple manner.

What I claim iszl. In an aircraft having a sustaining rotor,

relatively movable axis members with vertically spaced bearings therebetween, a sustaining blade articulated to an axis part on a substantially upright axis,y and vertically spaced articulation parts disposed adjacent -said vertically spaced an articulation bearing adja- 2.In an aircraft relatively movable axis parts with vertically spaced bearings therebetween, a sustaining blade,

0 .and means for securing said`blade to Van axis part, said means including flexible joint parts disposed adjacent said vertically spaced bearings to provide an axis for blade movements extended with l ranged for c j having a sustaining rotor,

movable with the said cooperating .part andaresilient device interposed between said abutment and a portion of the said structure.

6. In` an aircraft having a sustaining rotor, an axis structure, a sustaining blade, and means for pivoting said blade to said axis structure,

'said means including a substantially vertically extended pivot, a substantiallyehprizontally extended pivot and a joint part cooperating with 'said'pivots and movable with theblade about the substantially vertical pivot axis, together mechanism for controlling pivotal blade mov ents, said mechanism including an abutment movable with the said joint part and a resilient device interposed between said abutment anda portion of the said structure.

' 7. In an aircraft havinga sustaining rotor mounted for rotation about an upwardly extended axis, an axis structure, a sustaining vblade pivoted thereto, and means for controlling pivotal blade movements arrangedto react between-a part movable with the blade and said axis structure, there ,being a plurality `of sustaining vblades/pivoted -to the structure, together with a plurality of controlling means disposed about the axis structure between the points of pivotal attachment vof the blades, and each aroopexfation with a plurality of blades. 8. In ani/aircraft having a sustaining rotor, a

lmounting, structure for the rotor including a huir' structure having apertured lugs for pivotal attachment of sustaining blades thereto, the lugs being spacedl from each other about the axis, and meansl for controlling` pivotal bladev movements mounted on the hub structure between adjacent lugs. l

9. An aircraft having a sustaining biased ro- .f tor and ,a blade mounting structure, a forli` at pivot means joining the inner end of a blade, the dork to said structure, the pivot means including pivot joint parts providing for movement of the blade -on a substantially vertically extended axis, and means for controlling blade pivot movements about said vertical axis, said 120 means, being arranged react between said structure and a portion of said fork. 10. In an aircraft having a sustaining rotor,

'anaxis mechanism, a sustaining blade pivotally attached to the axis mechanism, yand means for controlling pivotal blade movements, said means substantially parallel to the axis of' ther said 5 laxis parts.` y

3. An aircraft having a sustaining rotor, and means for mounting the blades of the rotor ini cluding a common axis structure and joint means providing fof swinging movements of the blades Q9 4with respect to Isaid structure, said joint means lincluding parts providing one pivot axis extended generally vertically closely adjacent the said structure and another pivot axis extended generally horizontally at la point spaced radially M1; outwardly from the other joint axis, together ment movable with a blade pivot part, and a resilient device interposed between said abutment'vanda portion of the said structure.

5. In an aircraft having a sustaining rotor, an axis structure, a sustaining blade, and means m 'for'pivoting said blade to said axis structure',

said means including a substantially vertically extended pivot` and a cooperating pivot joint 1 part movable with-the blade, together with amechanism'for controlling pivotal blade movefments, said mechanism including an abutment including a resilient device mounted on a part movabie with the blade about its pivot axis and arranged to react against a part. not so movable.

the kmovablepart being socketed to receive the device, together with means for securing the saiddevice-irifthesocketed part.

11. For an aircraft of the pivoted and rotatively `mounted blade time. a mechanismfor controlling pivotal blade movements,v said mecha--l nisml includinga rubber bumper having means of attachment to a cooperating part, and said means beingv embedded in the rubber.

' 12.v For an aircraft of the pivoted and rotatively mounted blade type, a mechanism for con,

trolling 'pivotal blade movements. said mechanismincluding a rubber bumper having means of attachment toa cooperating part,- and said means in`c'luding an internally threaded collarembedded in the rubber.`

- 13. i hub v'structure for an aircraft sustaining rotor, said hub structure having strengthening flanges at top and bottom, a plurality of -blades connected vwith the hub, a rotor brake part attahed tothe lower flange, and means for 150 supporting the blades when they are inactive or at rest, saidmeans being secured to said upper flange. l

14. In an aircraft having a sustaining rotor, an axis structure, a sustaining blade pivoted thereto, and pivot joint parts including a pair of pivot pins and a block apertured to receive said pins, together `with means for fixing both of said pins as against rotation in said block.

15. In an aircraft having a sustaining rotor, an axis structure, a sustaining blade pivoted thereto, and pivot joint parts includig a pair of pivot pins, one extended generally vertically and the other extended generally horizontally, and a block apertured to receive said pins, the said pins being arranged for cooperative interengagement whereby one is positioned by the other, together with means for positioning the said other pin.

16. In an aircraft having a sustaining rotor, a hub structure for the rotor, a sustaining blade flexibly jointed to the hub structure, and exible joint parts including a pair of pivot pins arranged substantially tangentially to. each. other.

17. In an aircraft having a sustaining rotor, a hub structure for the rotor, a sustaining blade flexibly joined to the hub structure, and flexible joint parts including a pair of pivot pins arranged substantially tangentially to each other and having complementary interengaging parts formed to provide for positioning of one pin by engagement thereof with the other.

18. In a multi-bladed aircraft sustaining rotor, a hub structure to which the blades are pivotally connected, a structure extended above the hub and arranged for rotation therewith, and means for supporting the blades when they are inactivel or rotating below normal flight speeds, said means including support elements extended from the blades to the structure last mentioned and being joined to a device mounted for movement about the axis of the rotor, together with pivot joints connecting said elements with said device.

19. In a multi-bladed aircraft sustaining rotor, a hub structure to which the blades are pivotally connected on substantially horizontally extended and substantially vertically extended axes, a structure extended above the hub and arranged for rotation therewith, and means for supporting the blades when they are inactive or rotating below normal flight speeds, said means including support elements extended from the blades to the structure last mentioned and being joined to a device mounted for movement about the axis of the rotor, together with substantially horizontal and substantially vertical pivot joints connecting said elements with said device.

20. In an aircraft having. a sustaining rotor, rotor blades or wings, anaxis structure for said blades or wings, apivot device having a generally vertical pivot part joining a sustaining blade to the axis structure with freedom for force conipensating movements about a substantially vertically extended axis, and means for controlling force compensating blade movements, said means being disposed between a pivot part and a portion of the axis structure.

21. In an aircraft, a sustaining rotor lmechanism including a hub having a generally upright axis, a plurality of blades arranged around the hub for autorotational actuation under the influence of relative air-flow in flight, and pivot devices for securing each blade to the hub, said devices including a generally horizontal` pivot providing for upward and downward blade swinging movements, an additonal pivot the axis of which is extended at an angle tothe longitudinal axis of the blade and lies substantially in the plane containing the longitudinal axis of the blade and the upright axis of the rotor, said ad. ditional pivot further being positioned intermediate the generally horizontal pivot and the said rotor axis, and a lug on the hub for attachment of said additional pivot thereto, the lug being provided with an aperture to cooperate with the pivot and being extended from the main body of the hub a distance not greater than a fraction of the diameter of the hub, whereby to position said additional pivot in close proximity to the hub.

22. In an air craft, a sustaining rotor mechanism including a hub structure incorporating relatively rotatable elements, bearing means between said elements, a plurality of blades arranged around the hub for autorotational actuation under the influence of relative air flow in flight, and pivot devices for securing each blade to a hub element, said devices including a generally horizontal pivot providing for upward and downwardblade swinging movements, an additional pivot the axis of which is extended at an angle to the longitudinal axis of the blade and lies substantially in the plane containing the longitudinal axis of the blade and the upright axis of the rotor, said additional pivot being located between the pivot first mentioned and the axis of the rotor, and lug means secured to the hub element and cooperating with said addi tional pivot for mounting 'the additional pivoton the hub element, said lug means being disposed substantially radially outwardly of the bearing means and substantially in the plane thereof, whereby centrifugal and other forces incident to rotation are transmitted substantially directly from the lug means through the hub element which is rotatable with the rotor and through `the bearing means to the other hub element.

23. In an aircraft having a sustaining rotor,

- an axis structure, apertured lug means on the axis structure, a sustaining blade having apertured lug means. and pivot joint parts for pivotally connecting said two lug means including a pair of pivot pins and a block apertured to receive said pins, one pin cooperating with the lug means on the axis structure and the other with the lug means on the blade, together with means for fixing both of said pins as against rotation in said block to provide for pin movement within the apertures of the lug means.

JOSEPH s. EcKER. 

